Short-Baseline Neutrino Oscillation Anomalies and Light Sterile Neutrinos. Carlo Giunti

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1 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53 Short-Baseline Neutrino Oscillation Anomalies and Light Sterile Neutrinos Carlo Giunti INFN, Torino, Italy Seminar at Roma Tre November 07

2 Fermion Mass Spectrum C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53 m [ev] d u e ν e c s µ ν µ ν ν ν 3 t b τ ν τ 3 4

3 Neutrino Mixing C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 3/53 Left-handed Flavor Neutrinos produced in Weak Interactions ν e, ν µ, ν τ, H CC = g W ρ (ν el γ ρ e L + ν µl γ ρ µ L + ν τl γ ρ τ L ) + H.c. Fields ν αl = k U αk ν kl = ν α, = k U αk ν k, States ν, ν, ν 3, Left-handed Massive Neutrinos propagate from Source to Detector U e U e U e3 3 3 Unitary Mixing Matrix: U = U µ U µ U µ3 U τ U τ U τ3

4 Neutrino Oscillations C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 4/53 ν(t = 0) = ν α = U α ν + U α ν + U α3 ν 3 ν α source ν ν ν3 L ν β detector ν(t > 0) = U α e ie t ν + U α e ie t ν + U α3 e ie 3t ν 3 ν α E k = p + m k P να ν β (L) = ν β ν(l) = k,j t = L U βk U αk U βj U αj exp ( i m kj L E ) the oscillation probabilities depend on U and m kj m k m j

5 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 5/53 ν-mixing: ( m P να ν β = sin ϑ sin ) L 4E = L osc = 4πE m 0.8 Pνα ν β sin ϑ 0. 0 L osc L Tiny neutrino masses lead to observable macroscopic oscillation distances! ( m km ) short-baseline experiments m ev MeV GeV L E 3 ( m km ) long-baseline experiments m 3 ev MeV GeV 4 km atmospheric neutrino experiments m 4 ev GeV m solar neutrino experiments m ev MeV Neutrino oscillations are the optimal tool to reveal tiny neutrino masses!

6 Three-Neutrino Mixing Paradigm C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 6/53 U = = Standard Parameterization of Mixing Matrix (as CKM) 0 0 c 3 0 s 3 e iδ 3 c s c 3 s s c 0 0 e iλ 0 0 s 3 c 3 s 3 e iδ 3 0 c e iλ 3 c c 3 s c 3 s 3 e iδ s c 3 c s 3 s 3 e iδ 3 c c 3 s s 3 s 3 e iδ 3 s 3 c 3 0 e iλ 0 s s 3 c c 3 s 3 e iδ 3 c s 3 s c 3 s 3 e iδ 3 c 3 c e iλ 3 c ab cos ϑ ab s ab sin ϑ ab 0 ϑ ab π OSCILLATION PARAMETERS 0 δ 3, λ, λ 3 < π 3 Mixing Angles: ϑ, ϑ 3, ϑ 3 CPV Dirac Phase: δ 3 independent m kj m k m j : m, m 3 CPV Majorana Phases: λ, λ 3 L = processes

7 Three-Neutrino Mixing Ingredients C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 7/53 U = 0 0 c 3 0 s 3 e iδ 3 c s c 3 s s c 0 0 e iλ 0 0 s 3 c 3 s 3 e iδ 3 0 c e iλ 3 Solar ν e ν µ, ν τ VLBL Reactor ν e disappearance SNO, Borexino Super-Kamiokande GALLEX/GNO, SAGE Homestake, Kamiokande (KamLAND) ms = m ev sin ϑ S = sin ϑ 0.30

8 Three-Neutrino Mixing Ingredients C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 8/53 U = 0 0 c 3 0 s 3 e iδ 3 c s c 3 s s c 0 0 e iλ 0 0 s 3 c 3 s 3 e iδ 3 0 c e iλ 3 Atmospheric ν µ ν τ LBL Accelerator ν µ disappearance Super-Kamiokande Kamiokande, IMB MACRO, Soudan- ( KK, MINOS TK, NOνA ) ma m ev sin ϑ A = sin ϑ LBL Accelerator ν µ ν τ (OPERA)

9 Three-Neutrino Mixing Ingredients C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 9/53 U = 0 0 c 3 0 s 3 e iδ 3 c s c 3 s s c 0 0 e iλ 0 0 s 3 c 3 s 3 e iδ 3 0 c e iλ 3 LBL Accelerator ν µ ν e LBL Reactor ν e disappearance (TK, MINOS, NOνA) ( Daya Bay, RENO Double Chooz ma m ev ) sin ϑ 3 0.0

10 Mass Ordering C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53 m ν e ν µ ν τ m ν 3 ν m SOL ν m ATM m ATM ν m SOL ν Normal Ordering m 3 > m 3 > 0 ν 3 Inverted Ordering m 3 < m 3 < 0 absolute scale is not determined by neutrino oscillation data

11 Beyond Three-Neutrino Mixing: Sterile Neutrinos C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53 m. ν 5 ν 4. m SBL ν s ν s ev σ had [nb] 30 0 ALEPH DELPHI L3 OPAL average measurements, error bars increased by factor ν 3ν 4ν ν 3 ν ν m ATM m SOL ν e ν µ ν τ.5 3 ev ev E cm [GeV] N LEP ν active =.9840 ± Terminology: means: a ev-scale sterile neutrino a ev-scale massive neutrino which is mainly sterile

12 Sterile Neutrinos from Physics Beyond the SM Neutrinos are special in the Standard Model: the only neutral fermions Active left-handed neutrinos can mix with non-sm singlet fermions often called right-handed neutrinos Light left-handed anti-ν R are light sterile neutrinos ν c R ν sl (left-handed) Sterile means no standard model interactions [Pontecorvo, Sov. Phys. JETP 6 (968) 984] Active neutrinos (ν e, ν µ, ν τ ) can oscillate into light sterile neutrinos (ν s ) Observables: Disappearance of active neutrinos (neutral current deficit) Indirect evidence through combined fit of data (current indication) Short-baseline anomalies + 3ν-mixing: m m 3 m 4... ν ν ν 3 ν 4... ν e ν µ ν τ ν s... C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53

13 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 3/53 Here I consider sterile neutrinos with mass scale ev in light of short-baseline Reactor Anomaly, Gallium Anomaly, LSND. Other possibilities (not incompatible): Very light sterile neutrinos with mass scale ev: important for solar neutrino phenomenology [de Holanda, Smirnov, PRD 69 (004) 300; PRD 83 (0) 30] [Das, Pulido, Picariello, PRD 79 (009) 0730] Recent Daya Bay constraints for 3 m ev [PRL 3 (04) 480] Heavy sterile neutrinos with mass scale ev: could be Warm Dark Matter [Asaka, Blanchet, Shaposhnikov, PLB 63 (005) 5; Asaka, Shaposhnikov, PLB 60 (005) 7; Asaka, Shaposhnikov, Kusenko, PLB 638 (006) 40; Asaka, Laine, Shaposhnikov, JHEP 0606 (006) 053, JHEP 070 (007) 09] [Reviews: Kusenko, Phys. Rept. 48 (009) ; Boyarsky, Ruchayskiy, Shaposhnikov, Ann. Rev. Nucl. Part. Sci. 59 (009) 9; Boyarsky, Iakubovskyi, Ruchayskiy, Phys. Dark Univ. (0) 36; Drewes, IJMPE, (03) 33009]

14 Four-Neutrino Schemes: +, 3+ and +3 m ν 4 m ν m m m m ν m ATM m SOL ν 4 ν 4 ν 3 m SOL ν 3 ν m ATM ν m ATM ν m SOL ν ν 3 m SBL m SBL m SBL m SBL m SBL m SBL ν 3 ν m SOL ν ν 4 m ATM ν m ATM ν m SOL m ATM m SOL ν 4 ν 4 ν ν 3 ν ν C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 4/53

15 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 5/53 + Four-Neutrino Schemes m ν 4 m ν m ATM ν 3 m SOL ν m SBL m SBL m SOL ν ν m ATM ν 4 ν 3 After LSND (995) + was preferred to 3+, because of the 3+ appearance-disappearance tension [Okada, Yasuda, IJMPA (997) 3669; Bilenky, CG, Grimus, EPJC (998) 47] This is not a perturbation of 3-ν Mixing = Large active sterile oscillations for solar or atmospheric neutrinos!

16 + Schemes are Strongly Disfavored C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 6/53 50 χ solar + KamLAND solar solar (pre SNO salt) global solar + KamLAND χ PG χ PC atmospheric + 99% CL ( dof) atm + KK + SBL 99% CL Solar: Matter Effects + SNO NC η s η s Atmospheric: Matter Effects d µ η s = U s + U s = U s3 + U s4 99% CL: { ηs < 0.5 (Solar + KamLAND) η s > 0.75 (Atmospheric + KK) [Maltoni, Schwetz, Tortola, Valle, New J. Phys. 6 (004) ]

17 3+ and +3 Four-Neutrino Schemes m m m ν 4 ν 4 ν 3 msol matm ν matm msol ν m ν ν ν 3 m SBL m SBL m SBL m SBL ν 3 ν m SOL m ATM ν m ATM ν m SOL ν 4 ν 4 ν ν Perturbation of 3-ν Mixing: U e4, U µ4, U τ4 U s4 +3 schemes are disfavored by cosmology (ΛCDM): 3 m k 0. ev [Planck, Astron. Astrophys. 594 (06) A3 (arxiv: )] k= C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 7/53

18 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 8/53 Effective 3+ SBL Oscillation Probabilities Appearance (α β) ( ) m P SBL ( ) sin ϑ ν ( ) αβ sin 4 L α ν β 4E Disappearance ( ) m P SBL ( ) sin ϑ ν ( ) αα sin 4 L α ν α 4E sin ϑ αβ = 4 U α4 U β4 sin ϑ αα = 4 U α4 ( U α4 ) U e U e U e3 U e4 U µ U µ U µ3 U µ4 U = U τ U τ U τ3 U τ4 U s U s U s3 U s4 SBL 6 mixing angles 3 Dirac CP phases 3 Majorana CP phases CP violation is not observable in SBL experiments! Observable in LBL accelerator exp. sensitive to matm [de Gouvea et al, PRD 9 (05) , PRD 9 (05) 0730, arxiv: ; Palazzo et al, PRD 9 (05) 07307, PLB 757 (06) 4; Kayser et al, JHEP 5 (05) 039, JHEP 6 (06) ] and solar exp. sensitive to msol [Long, Li, CG, PRD 87, 3004 (03) 3004]

19 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 9/53 Common Parameterization of 4 4 Mixing Matrix U = [ W 34 R 4 W 4 R 3 W 3 R ] ( ) diag, e iλ, e iλ 3, e iλ 4 c c 3c 4 s c 3c 4 c 4s 3e iδ 3 s 4e iδ c 4s 4 0 e iλ 0 0 = c 4c 4s 34e iδ e iλ 3 0 c 4c 4c e iλ 4 U e4 = sin ϑ 4 sin ϑ ee = 4 U e4 ( U e4 ) = sin ϑ 4 U µ4 = cos ϑ 4 sin ϑ 4 sin ϑ 4 sin ϑ µµ = 4 U µ4 ( U µ4 ) sin ϑ 4

20 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 0/53 LSND [PRL 75 (995) 650; PRC 54 (996) 685; PRL 77 (996) 308; PRD 64 (00) 007] ν µ ν e 0 MeV E 5.8 MeV Well-known and pure source of ν µ p + target π + at rest µ + + ν µ 800 MeV µ + at rest e + + ν e + ν µ ν e + p n + e + Well-known detection process of ν e 3.8σ excess L 30 m m SBL 0. ev m ATM But signal not seen by KARMEN at L 8 m with the same method [PRD 65 (00) 00]

21 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53 MiniBooNE L 54 m ν µ ν e [PRL (009) 80] 00 MeV E 3 GeV ν µ ν e [PRL (03) 680] LSND signal LSND signal Purpose: check LSND signal. Different L and E. Similar L/E (oscillations). No money, no Near Detector. LSND signal: E > 475 MeV. Agreement with LSND signal? Low-energy anomaly MicroBooNE Pragmatic Approach: E > 475 MeV.

22 Gallium Anomaly C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 /53 Gallium Radioactive Source Experiments: GALLEX and SAGE ν e Sources: e + 5 Cr 5 V + ν e e + 37 Ar 37 Cl + ν e E 0.75 MeV E 0.8 MeV Test of Solar ν e Detection: ν e + 7 Ga 7 Ge + e R =N exp N cal GALLEX SAGE Cr Cr R = 0.84 ± 0.05 L GALLEX =.9 m GALLEX SAGE Cr Ar L SAGE = 0.6 m m SBL ev m ATM.9σ deficit [SAGE, PRC 73 (006) ; PRC 80 (009) 05807; Laveder et al, Nucl.Phys.Proc.Suppl. 68 (007) 344, MPLA (007) 499, PRD 78 (008) , PRC 83 (0) ] 3 He + 7 Ga 7 Ge + 3 H cross section measurement [Frekers et al., PLB 706 (0) 34]

23 Reactor Electron Antineutrino Anomaly C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 3/53 [Mention et al, PRD 83 (0) ] New reactor ν e fluxes [Mueller et al, PRC 83 (0) 05465; Huber, PRC 84 (0) 0467] R = N exp N cal Bugey 3 Bugey 4 Chooz Daya Bay Double Chooz Gosgen ILL Krasnoyarsk Nucifer 3 L [m].8σ deficit Palo Verde RENO Rovno88 R = ± 0.04 Rovno9 SRP

24 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 4/53 P ν e νe Bugey 4 Rovno9 E 4MeV sin ϑ ee = 0. m 4 = 0. ev m 4 = 0.5 ev m 4 =.0 ev Rovno88 Bugey 3 Gosgen ILL 3 L [m] Krasnoyarsk SRP Nucifer R DC DB DC R DB m SBL 0.5 ev m ATM SBL oscillations are averaged at the Daya Bay, RENO, and Double Chooz near detectors = no spectral distortion

25 E ( (Data - MC) / MC χ i ) Reactor Antineutrino 5 MeV Bump 5000 E (Data - MC) / MC Data / Predicted 0.5 MeV.4..0 Data No oscillation Reactor flux uncertainty Total systematic uncertainty Best fit: sin θ Prompt Energy (MeV) Prompt Energy Visible Energy (MeV) 4 [RENO, arxiv: ] [Double Chooz, arxiv: ] [Daya Bay, arxiv: ] Cannot be explained by neutrino oscillations (SBL oscillations are averaged in Double Chooz, Daya Bay, RENO). It is likely due to theoretical miscalculation of the spectrum. 3% effect on total flux, but if it is an excess it increases the anomaly! No post-bump complete calculation of the neutrino fluxes. Saclay-Huber flux calculation uncertainty is about.5%. = Entries / Ratio to Prediction (Huber + Mueller) contribution χ Integrated Prompt Energy (MeV) Increasing the flux uncertainty is a game that one can play, but there are only guesses, e.g. about 5%. [Hayes and Vogel, 06] Increasing the flux uncertainty decreases the statistical significance of the anomaly, but more anomaly is allowed in combined fits with other data! At the moment it is better to consider the calculated flux and uncertainties in order to predict the signal that must be tested in new experiments. C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 5/ Local p-value ( MeV windows)

26 ε C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 6/53 NEOS [PRL 8 (07) 80 (arxiv:6.0534)] Events /day/0 kev Data/Prediction Data/Prediction (a) (b) Prompt Energy [MeV] Data signal (ON-OFF) Data background (OFF) MC 3ν (H-M-V) MC 3ν (Daya Bay) NEOS/H-M-V Systematic total Neutrino Energy [MeV] (c) NEOS/Daya Prompt BayEnergy [MeV] Systematic total.0 (.73 ev, 0.050) (.3 ev, 0.4) Prompt Energy [MeV] 3 Hanbit Nuclear Power Complex in Yeong-gwang, Korea. Thermal power of.8 GW. Detector: a ton of Gd-loaded liquid scintillator in a gallery approximately 4 m from the reactor core. The measured antineutrino event rate is 976 per day with a signal to background ratio of about.

27 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 7/53 NEOS Spectrum 90% CL 95% CL 99% CL [ev ] m 4 3 sin ϑ ee Best Fits: m4 =.7 ev sin θ 4 = 0.05 m4 =.3 ev sin θ 4 = 0.04 χ no osc. χ min = 6.5 χ distribution:.σ anomaly NEOS Monte Carlo:.σ anomaly

28 Global ν e and ν e Disappearance [Gariazzo, CG, Laveder, Li, JHEP 706 (07) 35 (arxiv: )] ν edis σ σ 3σ KARMEN+LSND ν e C [Conrad, Shaevitz, PRD 85 (0) 0307] [CG, Laveder, PLB 706 (0) 0] [ev ] σ Reactors Gallium ν ec Sun TK Solar ν e + KamLAND ν e [Li et al, PRD 80 (009) 3007, PRD 86 (0) 304] [Palazzo, PRD 83 (0) 303, PRD 85 (0) 07730] m 4 TK Near Detector ν e disappearance [TK, PRD 9 (05) 05] χ NO /NDF NO = 4./ 3.3σ anom. sin ϑ ee Best Fit: m 4 =.7 ev L osc 4 = 4πE sin ϑ ee = U e4 = 0.07 m4 χ min /NDF = 63.0/74 GoF = 7% In agreement with Dentler, Hernandez-Cabezudo, Kopp, Maltoni, Schwetz, arxiv: C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 8/53

29 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 9/53 Tritium Beta-Decay: 3 H 3 He + e + ν e Q = M3 H M3 He m e = 8.58 kev dγ dt = (cosϑ C G F ) π 3 M F (E) p E K (T ) K (T ) Q T = k U ek (Q T ) m k θ(q T m k) m 4 m,,3 ( U e4 ) (Q T ) m β θ(q T m β) + U e4 (Q T ) m 4 θ(q T m 4) K(T) Q 3 mβ = U ek mk k= Q m 4 T Q m β

30 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 30/53 Mainz and Troitsk Limit on m 4 m 4 m 4 m,,3 = m 4 m 4 m m 4 [Kraus, Singer, Valerius, Weinheimer, EPJC 73 (03) 33] [Belesev et al, JPG 4 (04) 0500]

31 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 3/53 Global ν e and ν e Disappearance + β Decay [Gariazzo, CG, Laveder, Li, JHEP 706 (07) 35 (arxiv: )] ν edis+β 3σ σ σ 3σ ν edis β Best Fit: m 4 =.7 ev sin ϑ ee = U e4 = 0.07 [ev ] m 4 cm Losc 4 7 m at 3σ E [MeV] sin ϑ ee 0.3 at 3σ sin ϑ ee

32 The Race for ν e and ν e Disappearance C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 3/53 3 CeSOX shape (95% CL) CeSOX rate (95% CL) CeSOX rate+shape (95% CL) KATRIN (90% CL) ν edis+β σ σ 3σ 3 DANSS (yr, 95% CL) Neutrino 4 (yr, 95% CL) PROSPECT phase (3yr, 3σ) PROSPECT phase (3yr, 3σ) SoLiD phase (yr, 95% CL) SoLiD phase (3yr, 3σ) STEREO (yr, 95% CL) ν edis+β σ σ 3σ [ev ] m 4 [ev ] m sin ϑ ee sin ϑ ee CeSOX (Gran Sasso, Italy) 44 Ce ν e BOREXINO: L 5-m [Vivier@TAUP05] KATRIN (Karlsruhe, Germany) 3 H ν e [Drexlin@NOW06] DANSS (Kalinin, Russia) L -m [arxiv: ] Neutrino-4 (RIAR, Russia) L 6-m [JETP (05) 578] PROSPECT (ORNL, USA) L 7-m [arxiv:5.00] SoLid (SCK-CEN, Belgium) L 5-8m [arxiv: ] STEREO (ILL, France) L 8-m [arxiv: ]

33 ν µ ν e and ν µ ν e Appearance 99% CL LSND MiniBooNE KARMEN NOMAD BNL E776 ICARUS OPERA [ev ] m 4 ν µ ν e 90% CL 95% CL 99% CL 3 sin ϑ eµ C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 33/53

34 ν µ and ν µ Disappearance [ev ] m 4 99% CL CDHSW: νµ (984) CCFR: νµ (984) ATM: νµ + νµ SciBooNE MiniBooNE: νµ (0) SciBooNE MiniBooNE: νµ (0) IceCube: νµ + νµ (06) MINOS: νµ CC+NC (06) MINOS&MINOS+ (07) 3 sin ϑ µµ C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 34/53

35 [ev ] m 4 3+ Appearance-Disappearance Tension ν e DIS sin ϑ ee 4 U e4 3σ ν e Dis ν µ Dis Dis App ν µ ν e APP ν µ DIS sin ϑ µµ 4 U µ4 sin ϑ eµ = 4 U e4 U µ4 4 sin ϑ ee sin ϑ µµ [Okada, Yasuda, IJMPA (997) 3669; Bilenky, CG, Grimus, EPJC (998) 47] 4 3 sin ϑ eµ PrGlo6A σ σ 3σ ν µ ν e is quadratically suppressed! PrGlo6A = 06 data except MINOS and [Gariazzo, CG, Laveder, Li, JHEP 706 (07) 35] IceCube χ NO /NDF NO = 48.3/3 6.4σ anom. Best Fit: m 4 =.6 ev U e4 = 0.06 U m4 = 0.03 χ min /NDF = 6.0/44 GoF = 0% χ PG /NDF PG = 3.8/ GoF PG = 5% Similar tension in 3+, 3+3,..., 3+N s [CG, Zavanin, MPLA 3 (05) ] C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 35/53

36 Effects of MINOS and IceCube 3σ PrGlo6A PrGlo6A + MINOS PrGlo6A + IceCube PrGlo6A + MINOS + IceCube = PrGlo6B m 4 [ev ] 3σ MINOS IceCube sin ϑ µµ IceCube effect in agreement with Collin, Arguelles, Conrad, Shaevitz, PRL 7 (06) 80 Best Fit: m 4 =.6 ev U e4 = U µ4 = 0.0 χ min /NDF = 530.3/59 GoF = 36% χ PG /NDF PG = 4.7/ GoF PG = 9.7% More tension! C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 36/53

37 Effects of NEOS C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 37/53 3σ NEOS m 4 [ev ] 3σ PrGlo6B PrGlo7A sin ϑ ee Best Fit: m 4 =.7 ev U e4 = 0.00 U µ4 = 0.05 χ min /NDF = 595./579 GoF = 3% χ PG /NDF PG = 7./ GoF PG =.7% More tension!

38 New Bound from MINOS & MINOS+ [arxiv: ] ν µ mode POT MINOS POT MINOS+ 4 (ev ) m MINOS & MINOS+ data 90% C.L. MINOS 90% C.L. IceCube 90% C.L. Super-K 90% C.L. CDHS 90% C.L. CCFR 90% C.L. SciBooNE + MiniBooNE 90% C.L. Gariazzo et al. (06) 90% C.L ν µ mode 3 POT MINOS POT MINOS+ sin (θ 4 ) 4 (ev ) m 3 MINOS & MINOS+ data 90% C.L % C.L. Sensitivity ( σ and σ) 3 sin (θ 4 ) C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 38/53

39 Effects of MINOS & MINOS+ C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 39/53 3σ MINOS & MINOS+ m 4 [ev ] 3σ PrGlo7A PrGlo7B sin ϑ µµ Best Fit: m4 =.7 ev U e4 = 0.0 U µ4 = 0.0 χ min /NDF = 608.9/65 GoF = 56% χ PG /NDF PG =.9/ GoF PG = 0.43% More tension! The MINOS & MINOS+ bound disfavors the LSND ν µ ν e signal.

40 New Dedicated Experiments ( ) ν e ( ) ν e PrGlo7B PrGlo7B σ σ 3σ σ σ 3σ m 4 [ev ] m 4 [ev ] DANSS (yr, 95% CL) Neutrino 4 (yr, 95% CL) PROSPECT phase (3yr, 3σ) PROSPECT phase (3yr, 3σ) SoLiD phase (yr, 95% CL) SoLiD phase (3yr, 3σ) STEREO (yr, 95% CL) 3 CeSOX shape (95% CL) CeSOX rate (95% CL) CeSOX rate+shape (95% CL) KATRIN (90% CL) 3 sin ϑ ee sin ϑ ee C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 40/53

41 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 4/53 ( ) ν µ ( ) ν e SBN (3yr, 3σ) nuprism (3σ) JSNS (3σ) PrGlo7B σ σ 3σ ( ) ν µ ( ) ν µ [ev ] [ev ] m 4 m 4 PrGlo7B σ σ 3σ 4 3 SBN (3yr, 3σ) KPipe (3yr, 3σ) 3 sin ϑ eµ sin ϑ µµ

42 Neutrinoless Double-Beta Decay C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 4/ As 0 + β 76 3Ge β β 0 + Effective Majorana Neutrino Mass: m ββ = k 76 34Se U ek m k

43 Two-Neutrino Double-β Decay: L = 0 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 43/53 N (A, Z) N (A, Z + ) + e + e + ν e + ν e (T ν / ) = G ν M ν Ï Ù second order weak interaction process in the Standard Model Ï Ù Neutrinoless Double-β Decay: L = N (A, Z) N (A, Z + ) + e + e (T 0ν / ) = G 0ν M 0ν m ββ effective Majorana mass m ββ = Uek m k k Í Ñ Í Ï Ï Ù Ù

44 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 44/53 f(t) Ge νββ T [MeV] 0νββ Q =.039MeV

45 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 45/53 Effective Majorana Neutrino Mass m ββ = k U ek m k complex U ek possible cancellations m ββ = U e m + U e e iα m + U e3 e iα 3 m 3 α = λ α 3 = (λ 3 δ 3 ) Im[m ββ ] m ββ U e3m 3 Im[m ββ ] α 3 m ββ = 0 U em α 3 U e3m 3 U em U em α Re[m ββ ] α U em Re[mββ ]

46 Predictions of 3ν-Mixing Paradigm mββ = Ue m + Ue e iα m + Ue3 e iα3 m3 3ν Normal Ordering 3ν Inverted Ordering σ σ 3σ σ σ 3σ [ev] [ev] Uek mk Uek mk Ue m Ue m 3 Ue m Ue3 m3 3 Ue3 m3 Ue m Lightest mass: m 4 [ev] Lightest mass: m3 [ev] 90% C.L. UPPER LIMIT 90% C.L. UPPER LIMIT 3ν Normal Ordering (+,+) (+, ) (,+) (, ) σ σ 3σ CPV Lightest mass: m [ev] mββ [ev] [ev] mββ 3 3ν Inverted Ordering (+,+) (+, ) (,+) (, ) σ σ 3σ CPV Lightest mass: m3 [ev] C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 46/53

47 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 47/53 3+ Mixing m ββ = U e m + U e e iα m + U e3 e iα 3 m 3 + U e4 e iα 4 m 4 χ PrGlo7B 99.73% 99% 95.45% 90% 68.7% (4) m ββ [ev] m (k) ββ = U ek m k m m 4 m (4) ββ U e4 m 4 warning: possible cancellation with m (3ν) ββ [Barry, Rodejohann, Zhang, JHEP 07 (0) 09] [Li, Liu, PLB 706 (0) 406] [Rodejohann, JPG 39 (0) 4008] [Girardi, Meroni, Petcov, JHEP 3 (03) 46] [CG, Zavanin, JHEP 07 (05) 7]

48 Normal 3ν Ordering ν4 Inverted 3ν Ordering σ σ 3σ σ σ 3σ Ue m Ue4 m4 [ev] [ev] Ue4 m4 Uek mk Uek mk ν4 σ σ 3σ σ σ 3σ Ue m Ue m Ue3 m3 3 3 Ue3 m3 Ue m Lightest mass: m 4 [ev] 3ν (3σ) 3+ (3σ) [ev] KamLAND Zen, PRL 7 (06) % C.L. UPPER LIMIT [ev] mββ [ev] m3 Inverted 3ν Ordering KamLAND Zen, PRL 7 (06) % C.L. UPPER LIMIT mββ Lightest mass: Normal 3ν Ordering 3ν (3σ) 3+ (3σ) Lightest mass: m [ev] 4 3 Lightest mass: m3 [ev] C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 48/53

49 Daya Bay Reactor Fuel Evolution [Daya Bay, PRL 8 (07) 580 (arxiv:704.08)] Fission fraction (%) Reactor ν e flux produced by the β decays of the fission products of 35 U, 38 U, 39 Pu, 4 Pu. Effective fission fractions: F 35, F 38, F 39, F U 39 Pu 38 U 4 Pu Others Burn-up (MWD/TU) Cross section per fission: σ f = F k σ f,k k=35,38,39,4 σ f,k = de ν φ k (E ν ) σ(e ν ) σ f / σ f SH OSC C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 49/53 F 39

50 σ39 [ 43 cm / fission] Daya Bay Huber model w/ 68% C.L. σ38 = (. ±. 0) 43 σ4 = (6. 04 ± 0. 60) 43 C.L 68% 95% 99.7% σ35 [ 43 cm / fission] 9 χ Best fit: mainly suppression of σ f,35 Equal fluxes suppression: χ /NDF = 7.9/ disfavored at.8σ Equal fluxes suppression corresponds to SBL oscillations, but theoretical flux uncertainties must be taken into account χ σ f,39 / σf,39 SH σ f,35 / σ f,35 SH σ σ 3σ χ With theoretical flux uncertainties: Daya Bay χ min NDF GoF 35 U % OSC % MC: OSC disfavored at.6σ [CG, X.P. Ji, M. Laveder, Y.F. Li, B.R. Littlejohn, arxiv: ] C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 50/53

51 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 5/53 Fuel Fractions of All Reactor Experiments F i SRP 4 SRP 8 Krasnoyarsk99 34 Krasnoyarsk94 57 Krasnoyarsk87 9 Krasnoyarsk87 33 ILL Nucifer Daya Bay 0.5 Gosgen 38 Rovno88 I Rovno88 S Rovno88 S Rovno9 Daya Bay 0.74 Rovno88 I Palo Verde Daya Bay 0.87 Gosgen 46 Daya Bay 0.99 RENO Rovno88 S Daya Bay 0.3 Gosgen 65 Daya Bay 0.3 Bugey 3 95 Bugey 3 40 Bugey 3 5 Bugey 4 Daya Bay 0.33 Daya Bay Double Chooz F 35 F 38 F 39 F 4 Chooz

52 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 5/53 All Reactors χ min NDF GoF 35 U % OSC % σ f / σ f th OSC MC: 35 U disfavored at.7σ L [m] 3 Bugey 4 Bugey 3 5 Rovno9 Rovno88 I Rovno88 I Rovno88 S Rovno88 S SRP 8 SRP 4 Rovno88 S Krasnoyarsk87 33 Krasnoyarsk99 34 Gosgen 38 Bugey 3 40 Gosgen 46 Krasnoyarsk94 57 Gosgen 65 Krasnoyarsk87 9 Bugey 3 95 RENO Double Chooz Daya Bay Palo Verde Chooz Nucifer ILL

53 C. Giunti SBL Neutrino Oscillation Anomalies and Light Sterile Neutrinos Roma Tre Nov 07 53/53 Conclusions Exciting indications of sterile neutrinos (new physics!) at the ev scale: LSND ν µ ν e signal (caveat: single experimental signal). Gallium νe disappearance (caveat: overestimated detector efficiency?). Reactor νe disappearance (caveat: flux calculation dependence). The MINOS & MINOS+ bound disfavors the LSND ν µ ν e signal. Vigorous experimental program to check conclusively in a few years: ν e and ν e disappearance with reactors and radioactive sources. νµ ν e transitions with accelerator neutrinos. νµ disappearance with accelerator neutrinos. Independent tests through effect of m 4 in β-decay and ββ 0ν -decay. Cosmology: strong tension with N eff = and m 4 ev. It may be solved by a non-standard cosmological mechanism. Possibilities for the next years: Reactor and source experiments ν e and ν e observe SBL oscillations: big excitement and explosion of the field. Otherwise: still marginal interest to check the LSND appearance signal. In any case the possibility of the existence of sterile neutrinos related to New Physics beyond the Standard Model at different mass scales will continue to be studied (e.g kev sterile neutrinos).